Not all criticism is wrapped in a pretty package, but most of it is still useful. You are not your code, if someone attacks your code/product try to get to the useful part of that criticism and don't get bent out of shape about the insults.

I agree people should be more polite but there are some that are just incapable of wrapping their criticism up to be nice.

Speaking on the mentor portion of the article as a Junior Dev I worked under an older Senior Programmer who would flat out say the code I just finished and was proud of sucked, after asking a few questions I'd get to the root of it and learn something. Under the crude insults he was a smart guy who knew his stuff. The way he reviewed code was just part of his personality, he actively tried to be nice but it never came out to others as nice as he thought it was. In the end I'm glad he gave me criticism even if it wasn't pretty, it really helped me to hone my skills.